The present invention relates generally to control knobs that typically are used on control panels in automobiles, and, more particularly, to collapsing control knob assemblies having control knobs.
The automobile industry continually strives to produce safer and more reliable vehicles. Safety features are being incorporated into all subsystems and components of the automobile. At the same time, automakers continually strive to develop more styles, appearances and convenience features to make their products unique in comparison to those of competitors. While improving safety is a constant, primary concern, the competing desires of safety and styling are often in conflict with each other. Thus, automobile designers are asked to design vehicle components that promote safety and convenience and yet must be aesthetically pleasing to the consumer. To please a variety of customers, different design offerings are necessary.
Many safety standards in the automobile industry are intended to improve crash-worthiness of a vehicle, and to prevent, or at least minimize, injuries that may occur to occupants in the event of a crash. One such standard requires that all components on the automobile dashboard collapse in the event of an impact collision. After collapse, no sharp edges can be present, and all control knobs, buttons and the like should protrude only minimally from the surface. A current standard limits the allowable protrusion of knobs or controls to nine millimeters or less. The collapsing action of the dashboard and its components is sometimes referred to as xe2x80x9chomoligationxe2x80x9d. To meet this standard over all, any and all components such as air control heads that contain buttons or knobs, and other dashboard subsystems must individually meet the collapsing requirement.
To meet the standards limiting maximum protrusion of dashboard components, some automobile designers have reduced or even eliminated the use of rotary knobs that must collapse in the event of a crash. Depressible switches in the form of pads are used to toggle through, and select from the various functions that are controlled by the switch. A control panel having only depressible pads readily meets the maximum protrusion standards; however, some consumers find the appearance unpleasing, and the use of touchpad controls difficult, particularly by the driver while driving.
It is known to provide collapsing or telescoping buttons or knobs on control shafts. In one known construction, a D-shaft is received in a D-shaped opening of a control knob. The D-shaped opening in the knob is sufficiently deep, and the D-shaped portion of the shaft is sufficiently long that, upon a collision or other collapsing impact, the knob is shoved further onto the shaft, to reduce protrusion of the knob. While this design meets the collapsing requirements, it is necessary that the shape of the knob and the shape of the shaft are complementary. Further, the shaped portion of the shaft must be of sufficient length for the knob to slide further on during a crash. Thus, it is necessary to stock different style knobs for each style shaft used on control items, and to provide shafts having long knob receiving end segments sufficient for the knob to be used. A further problem with this design occurs during normal assembly. Without incorporating the collapsing feature, the length of the D-shaped portion of the shaft is only as long as necessary to receive the knob thereon. During assembly, the knob is slid onto the shaft until it will progress no farther. A natural xe2x80x9cstopxe2x80x9d is provided, making it easy to install all knobs to the proper depth. By allowing extra room for collapse, it becomes necessary to otherwise control the depth to which the knob is installed.
What is needed is a collapsing control having a knob adapted for use on shafts of standard types, but with the knob incorporating the collapsing feature required to meet safety standards.
The present invention provides a collapsible control knob assembly in which a control knob has stops establishing a fixed position of the knob on the shaft during assembly, with the stops being severable during a crash to collapse the control knob assembly.
In one aspect thereof, the present invention provides a collapsible control knob assembly with a shaft having a distal end and an end portion inwardly of the distal end. A knob has a head and a trunk, the trunk extending outwardly from the head and having a tunnel therein defined by a tunnel surface. The tunnel has an opening at an end of the trunk opposite the head. The tunnel is adapted to receive the end portion of the shaft. The tunnel has at least one rib extending radially inwardly from the tunnel surface. The rib has a rib end inwardly in the tunnel from the opening adapted to abut the shaft. The shaft is adapted to shear the at least one rib from the tunnel surface when a force from a collapsing event exceeds a pre-established limit, forcing the shaft and the knob toward each other.
In another aspect thereof, the present invention provides a collapsible control knob assembly with a shaft having an end and an end portion, and a knob slidable over the end portion. At least one stop in the knob abuts the shaft end. Shearing means shears the stop upon a compressive force between the shaft and the knob exceeding a selected limit.
In a further aspect thereof, the present invention provides an automobile control knob with a head, a trunk connected to the head, a tunnel in the trunk and at least one shearable stop disposed in the tunnel.
An advantage of the present invention is providing a collapsible control knob assembly that is easy to assemble.
A further advantage of the present invention is providing a collapsible control knob that operates with common shaft designs, and does not require special shaft configurations for proper homoligation.
Still another advantage of the present invention is providing a collapsible control knob design that is adaptable for manufacture to withstand different force limits without collapsing.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.